<?php
/**
 * CMssqlSchema class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Christophe Boulain <Christophe.Boulain@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright 2008-2013 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CMssqlSchema is the class for retrieving metadata information from a MS SQL Server database.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Christophe Boulain <Christophe.Boulain@gmail.com>
 * @package system.db.schema.mssql
 */
class CMssqlSchema extends CDbSchema
{
    const DEFAULT_SCHEMA = 'dbo';

    /**
     * @var array the abstract column types mapped to physical column types.
     * @since 1.1.6
     */
    public $columnTypes = array(
        'pk' => 'int IDENTITY PRIMARY KEY',
        'string' => 'varchar(255)',
        'text' => 'text',
        'integer' => 'int',
        'float' => 'float',
        'decimal' => 'decimal',
        'datetime' => 'datetime',
        'timestamp' => 'timestamp',
        'time' => 'time',
        'date' => 'date',
        'binary' => 'binary',
        'boolean' => 'bit',
    );

    /**
     * Quotes a table name for use in a query.
     * A simple table name does not schema prefix.
     * @param string $name table name
     * @return string the properly quoted table name
     * @since 1.1.6
     */
    public function quoteSimpleTableName($name)
    {
        return '[' . $name . ']';
    }

    /**
     * Quotes a column name for use in a query.
     * A simple column name does not contain prefix.
     * @param string $name column name
     * @return string the properly quoted column name
     * @since 1.1.6
     */
    public function quoteSimpleColumnName($name)
    {
        return '[' . $name . ']';
    }

    /**
     * Compares two table names.
     * The table names can be either quoted or unquoted. This method
     * will consider both cases.
     * @param string $name1 table name 1
     * @param string $name2 table name 2
     * @return boolean whether the two table names refer to the same table.
     */
    public function compareTableNames($name1, $name2)
    {
        $name1 = str_replace(array('[', ']'), '', $name1);
        $name2 = str_replace(array('[', ']'), '', $name2);
        return parent::compareTableNames(strtolower($name1), strtolower($name2));
    }

    /**
     * Resets the sequence value of a table's primary key.
     * The sequence will be reset such that the primary key of the next new row inserted
     * will have the specified value or max value of a primary key plus one (i.e. sequence trimming).
     * @param CDbTableSchema $table the table schema whose primary key sequence will be reset
     * @param integer|null $value the value for the primary key of the next new row inserted.
     * If this is not set, the next new row's primary key will have the max value of a primary
     * key plus one (i.e. sequence trimming).
     * @since 1.1.6
     */
    public function resetSequence($table, $value = null)
    {
        if ($table->sequenceName === null)
            return;
        if ($value !== null)
            $value = (int)($value) - 1;
        else
            $value = (int)$this->getDbConnection()
                ->createCommand("SELECT MAX([{$table->primaryKey}]) FROM {$table->rawName}")
                ->queryScalar();
        $name = strtr($table->rawName, array('[' => '', ']' => ''));
        $this->getDbConnection()
            ->createCommand("DBCC CHECKIDENT ('$name',RESEED,$value)")
            ->execute();
    }

    private $_normalTables = array(); // non-view tables
    /**
     * Enables or disables integrity check.
     * @param boolean $check whether to turn on or off the integrity check.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * @since 1.1.6
     */
    public function checkIntegrity($check = true, $schema = '')
    {
        $enable = $check ? 'CHECK' : 'NOCHECK';
        if (!isset($this->_normalTables[$schema]))
            $this->_normalTables[$schema] = $this->findTableNames($schema, false);
        $db = $this->getDbConnection();
        foreach ($this->_normalTables[$schema] as $tableName) {
            $tableName = $this->quoteTableName($tableName);
            $db->createCommand("ALTER TABLE $tableName $enable CONSTRAINT ALL")->execute();
        }
    }

    /**
     * Loads the metadata for the specified table.
     * @param string $name table name
     * @return CMssqlTableSchema driver dependent table metadata. Null if the table does not exist.
     */
    protected function loadTable($name)
    {
        $table = new CMssqlTableSchema;
        $this->resolveTableNames($table, $name);
        //if (!in_array($table->name, $this->tableNames)) return null;
        $table->primaryKey = $this->findPrimaryKey($table);
        $table->foreignKeys = $this->findForeignKeys($table);
        if ($this->findColumns($table)) {
            return $table;
        } else
            return null;
    }

    /**
     * Generates various kinds of table names.
     * @param CMssqlTableSchema $table the table instance
     * @param string $name the unquoted table name
     */
    protected function resolveTableNames($table, $name)
    {
        $parts = explode('.', str_replace(array('[', ']'), '', $name));
        if (($c = count($parts)) == 3) {
            // Catalog name, schema name and table name provided
            $table->catalogName = $parts[0];
            $table->schemaName = $parts[1];
            $table->name = $parts[2];
            $table->rawName = $this->quoteTableName($table->catalogName) . '.' . $this->quoteTableName($table->schemaName) . '.' . $this->quoteTableName($table->name);
        } elseif ($c == 2) {
            // Only schema name and table name provided
            $table->name = $parts[1];
            $table->schemaName = $parts[0];
            $table->rawName = $this->quoteTableName($table->schemaName) . '.' . $this->quoteTableName($table->name);
        } else {
            // Only the name given, we need to get at least the schema name
            //if (empty($this->_schemaNames)) $this->findTableNames();
            $table->name = $parts[0];
            $table->schemaName = self::DEFAULT_SCHEMA;
            $table->rawName = $this->quoteTableName($table->schemaName) . '.' . $this->quoteTableName($table->name);
        }
    }

    /**
     * Gets the primary key column(s) details for the given table.
     * @param CMssqlTableSchema $table table
     * @return mixed primary keys (null if no pk, string if only 1 column pk, or array if composite pk)
     */
    protected function findPrimaryKey($table)
    {
        $kcu = 'INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
        $tc = 'INFORMATION_SCHEMA.TABLE_CONSTRAINTS';
        if (isset($table->catalogName)) {
            $kcu = $table->catalogName . '.' . $kcu;
            $tc = $table->catalogName . '.' . $tc;
        }

        $sql = <<<EOD
		SELECT k.column_name field_name
		FROM {$this->quoteTableName($kcu)} k
		LEFT JOIN {$this->quoteTableName($tc)} c
		ON k.table_name = c.table_name
			AND k.constraint_name = c.constraint_name
		WHERE c.constraint_type ='PRIMARY KEY'
			AND k.table_name = :table
			AND k.table_schema = :schema
EOD;
        $command = $this->getDbConnection()->createCommand($sql);
        $command->bindValue(':table', $table->name);
        $command->bindValue(':schema', $table->schemaName);
        $primary = $command->queryColumn();
        switch (count($primary)) {
            case 0: // No primary key on table
                $primary = null;
                break;
            case 1: // Only 1 primary key
                $primary = $primary[0];
                break;
        }
        return $primary;
    }

    /**
     * Gets foreign relationship constraint keys and table name
     * @param CMssqlTableSchema $table table
     * @return array foreign relationship table name and keys.
     */
    protected function findForeignKeys($table)
    {
        $rc = 'INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS';
        $kcu = 'INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
        if (isset($table->catalogName)) {
            $kcu = $table->catalogName . '.' . $kcu;
            $rc = $table->catalogName . '.' . $rc;
        }

        //From http://msdn2.microsoft.com/en-us/library/aa175805(SQL.80).aspx
        $sql = <<<EOD
		SELECT
		     KCU1.CONSTRAINT_NAME AS 'FK_CONSTRAINT_NAME'
		   , KCU1.TABLE_NAME AS 'FK_TABLE_NAME'
		   , KCU1.COLUMN_NAME AS 'FK_COLUMN_NAME'
		   , KCU1.ORDINAL_POSITION AS 'FK_ORDINAL_POSITION'
		   , KCU2.CONSTRAINT_NAME AS 'UQ_CONSTRAINT_NAME'
		   , KCU2.TABLE_NAME AS 'UQ_TABLE_NAME'
		   , KCU2.COLUMN_NAME AS 'UQ_COLUMN_NAME'
		   , KCU2.ORDINAL_POSITION AS 'UQ_ORDINAL_POSITION'
		FROM {$this->quoteTableName($rc)} RC
		JOIN {$this->quoteTableName($kcu)} KCU1
		ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
		   AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
		   AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
		JOIN {$this->quoteTableName($kcu)} KCU2
		ON KCU2.CONSTRAINT_CATALOG =
		RC.UNIQUE_CONSTRAINT_CATALOG
		   AND KCU2.CONSTRAINT_SCHEMA =
		RC.UNIQUE_CONSTRAINT_SCHEMA
		   AND KCU2.CONSTRAINT_NAME =
		RC.UNIQUE_CONSTRAINT_NAME
		   AND KCU2.ORDINAL_POSITION = KCU1.ORDINAL_POSITION
		WHERE KCU1.TABLE_NAME = :table
EOD;
        $command = $this->getDbConnection()->createCommand($sql);
        $command->bindValue(':table', $table->name);
        $fkeys = array();
        foreach ($command->queryAll() as $info) {
            $fkeys[$info['FK_COLUMN_NAME']] = array($info['UQ_TABLE_NAME'], $info['UQ_COLUMN_NAME'],);

        }
        return $fkeys;
    }


    /**
     * Collects the table column metadata.
     * @param CMssqlTableSchema $table the table metadata
     * @return boolean whether the table exists in the database
     */
    protected function findColumns($table)
    {
        $columnsTable = "INFORMATION_SCHEMA.COLUMNS";
        $where = array();
        $where[] = "t1.TABLE_NAME='" . $table->name . "'";
        if (isset($table->catalogName)) {
            $where[] = "t1.TABLE_CATALOG='" . $table->catalogName . "'";
            $columnsTable = $table->catalogName . '.' . $columnsTable;
        }
        if (isset($table->schemaName))
            $where[] = "t1.TABLE_SCHEMA='" . $table->schemaName . "'";

        $sql = "SELECT t1.*, columnproperty(object_id(t1.table_schema+'.'+t1.table_name), t1.column_name, 'IsIdentity') AS IsIdentity, " .
            "CONVERT(VARCHAR, t2.value) AS Comment FROM " . $this->quoteTableName($columnsTable) . " AS t1 " .
            "LEFT OUTER JOIN sys.extended_properties AS t2 ON t1.ORDINAL_POSITION = t2.minor_id AND " .
            "object_name(t2.major_id) = t1.TABLE_NAME AND t2.class=1 AND t2.class_desc='OBJECT_OR_COLUMN' AND t2.name='MS_Description' " .
            "WHERE " . join(' AND ', $where);
        try {
            $columns = $this->getDbConnection()->createCommand($sql)->queryAll();
            if (empty($columns))
                return false;
        } catch (Exception $e) {
            return false;
        }

        foreach ($columns as $column) {
            $c = $this->createColumn($column);
            if (is_array($table->primaryKey))
                $c->isPrimaryKey = in_array($c->name, $table->primaryKey);
            else
                $c->isPrimaryKey = strcasecmp($c->name, $table->primaryKey) === 0;

            $c->isForeignKey = isset($table->foreignKeys[$c->name]);
            $table->columns[$c->name] = $c;
            if ($c->autoIncrement && $table->sequenceName === null)
                $table->sequenceName = $table->name;
        }
        return true;
    }

    /**
     * Creates a table column.
     * @param array $column column metadata
     * @return CDbColumnSchema normalized column metadata
     */
    protected function createColumn($column)
    {
        $c = new CMssqlColumnSchema;
        $c->name = $column['COLUMN_NAME'];
        $c->rawName = $this->quoteColumnName($c->name);
        $c->allowNull = $column['IS_NULLABLE'] == 'YES';
        if ($column['NUMERIC_PRECISION_RADIX'] !== null) {
            // We have a numeric datatype
            $c->size = $c->precision = $column['NUMERIC_PRECISION'] !== null ? (int)$column['NUMERIC_PRECISION'] : null;
            $c->scale = $column['NUMERIC_SCALE'] !== null ? (int)$column['NUMERIC_SCALE'] : null;
        } elseif ($column['DATA_TYPE'] == 'image' || $column['DATA_TYPE'] == 'text')
            $c->size = $c->precision = null;
        else
            $c->size = $c->precision = ($column['CHARACTER_MAXIMUM_LENGTH'] !== null) ? (int)$column['CHARACTER_MAXIMUM_LENGTH'] : null;
        $c->autoIncrement = $column['IsIdentity'] == 1;
        $c->comment = $column['Comment'] === null ? '' : $column['Comment'];

        $c->init($column['DATA_TYPE'], $column['COLUMN_DEFAULT']);
        return $c;
    }

    /**
     * Returns all table names in the database.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * If not empty, the returned table names will be prefixed with the schema name.
     * @param boolean $includeViews whether to include views in the result. Defaults to true.
     * @return array all table names in the database.
     */
    protected function findTableNames($schema = '', $includeViews = true)
    {
        if ($schema === '')
            $schema = self::DEFAULT_SCHEMA;
        if ($includeViews)
            $condition = "TABLE_TYPE in ('BASE TABLE','VIEW')";
        else
            $condition = "TABLE_TYPE='BASE TABLE'";
        $sql = <<<EOD
SELECT TABLE_NAME FROM [INFORMATION_SCHEMA].[TABLES]
WHERE TABLE_SCHEMA=:schema AND $condition
EOD;
        $command = $this->getDbConnection()->createCommand($sql);
        $command->bindParam(":schema", $schema);
        $rows = $command->queryAll();
        $names = array();
        foreach ($rows as $row) {
            if ($schema == self::DEFAULT_SCHEMA)
                $names[] = $row['TABLE_NAME'];
            else
                $names[] = $schema . '.' . $row['TABLE_NAME'];
        }

        return $names;
    }

    /**
     * Creates a command builder for the database.
     * This method overrides parent implementation in order to create a MSSQL specific command builder
     * @return CDbCommandBuilder command builder instance
     */
    protected function createCommandBuilder()
    {
        return new CMssqlCommandBuilder($this);
    }

    /**
     * Builds a SQL statement for renaming a DB table.
     * @param string $table the table to be renamed. The name will be properly quoted by the method.
     * @param string $newName the new table name. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB table.
     * @since 1.1.6
     */
    public function renameTable($table, $newName)
    {
        return "sp_rename '$table', '$newName'";
    }

    /**
     * Builds a SQL statement for renaming a column.
     * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method.
     * @param string $name the old name of the column. The name will be properly quoted by the method.
     * @param string $newName the new name of the column. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB column.
     * @since 1.1.6
     */
    public function renameColumn($table, $name, $newName)
    {
        return "sp_rename '$table.$name', '$newName', 'COLUMN'";
    }

    /**
     * Builds a SQL statement for changing the definition of a column.
     * @param string $table the table whose column is to be changed. The table name will be properly quoted by the method.
     * @param string $column the name of the column to be changed. The name will be properly quoted by the method.
     * @param string $type the new column type. The {@link getColumnType} method will be invoked to convert abstract column type (if any)
     * into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
     * For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
     * @return string the SQL statement for changing the definition of a column.
     * @since 1.1.6
     */
    public function alterColumn($table, $column, $type)
    {
        $type = $this->getColumnType($type);
        $sql = 'ALTER TABLE ' . $this->quoteTableName($table) . ' ALTER COLUMN '
            . $this->quoteColumnName($column) . ' '
            . $this->getColumnType($type);
        return $sql;
    }
}
